Improvement in ratchet-feed mechanisms



'UNITED 'STATES- PATENT OFFICE@ ANDREW TURNBULL, CF NEW BRITAIN,CONNECTICUT.

IMPROVEMENT IN RATCHET-FEED MECHANISMS.

Specification forming part of Letters Patent N0. 107,567, datedSeptember 20, 1870.

To all 'whom it may concern:

Be it known that I, ANDREW TURNBULL, of New Britain, Hartford county,and the State of Connecticut, have invented certain Improvements in aSubstitute fora Ratchet-Feed Mechanism, of which the following is aspecification.

In working hand-drills, where the surrounding circumstances are such asnot to permit the entire revolution of the arm by which the drill isworked, it is necessary to have the said arm so attached to the shaftwhich holds the drill that when the arm swings in one direction it willcarry the drill with it; but when swung in the opposite direction thedrill remains stationary. Such an arrangement is called a ratchetfeed.77As commonly constructed they have a circular ratchet with teeth, overwhich slides a pawl attached to the workin g-arm, which pawl catches inthe teeth when the arm is swung in one direction, but slips over theteeth when swung in the opposite direction. This arrangement is a noisyone, and causes a loss of motion, as the arm will almost always swing soas to carry the pawl beyond the catching-point of one tooth of theratchet, and not far enough to catch on the next; and, again, so far asthe inventor herein is informed, such a ratchet-feed permits the use ofbut one working-arm.

Myimprovement isintended to cure all these defects completely. It isperfectly noiseless in its operation. It has no lost motion. It admitsof the use oftwo working-arms, thus keeping up a continuous rotation ofthe shaft.

In the accompanying drawings, Figure lis a plan View. Fig. 2 is acentral vertical section.

The letter a indicates the shaft, which carries the drill which is to beinserted in the slot at the lower end, b.

The letter c indicates a disk fastened rigidly to the shaft a. At itscircumference it turns upward at a right angle, so as to form a shell orrim, against the inside of which the small cams e and e impinge. Thesesmall cams are attached to the under sides of the arms f and f,respectively, by pins i z', (seen in Fig. 1,) upon which they turnfreely. The arms f and j" have sockets or bearings o and o',respectively, which slip upon the shaft and turn thereon freely. The armf being attached to the upper part of its bearing o, and the armf beingattached to its bearing o at its lower part, the two arms are thusbrought to vibrate in the same plane. These small cams c and c` are soshaped that when the arms are rotated in the direction indicated by thearrow they will wedge in between their pivoting-pins 1J i and the insideof the rim of the disk c, and rotate the diskand thus the shaft a. withthem. When the armsarc moved in thc opposite direction the cams willslip on the rim. The springs s s', (seen in dotted lines in Fig. 1,)being on the under side of the arms, make the operation of the camssure. It will be observed that the spring s presses flatly against theside of its cam, while the spring s presses against the end of the cam ein such a manner as to in effect press its cam in the same direction asthe spring s presses the cam e. The collar x fits down and tightens by aset-screw upon both the bearings o and o', and thus keeps them in place.

From the above description it will be readily understood that it' thearms fandf are first opened from each other, and then shut together, oneof the cams will be acting all the while and a continuous rotation willbe kept up of the shaft a. It is perfectly noiseless in operation Yandloses no motion whatever.

One arm can be used for working this feedmechanism instead of two, ifdesired; but in that case it will not have a continuous rotary motion.It is also obvious that one of these cams will serve a useful purpose inany mechanism where it is desired to have a shaft turn but one way andnever to retrograde, such as in sewing-machines, lawn-mowers, and thelike.

I claim as my invention- 1. The combination of the shaft a, arm f, came, spring s, and disk o, the ,whole constructed, arranged, and operatedas described.

2. The combination ofthe shaft a,armsfand f', cams e and e', springs sand s', and the disk c, the whole constructed substantially as clelscribed, for the purpose set forth.

' ANDREW TURNBULL.

Witnesses WM. ED. SIMoNDs, FRANCIS N. FRosfr.

